Llanelli completed their Heineken Cup pool campaign unbeaten, but they were made to work desperately hard for the points against a gutsy London Irish side.

After leading 17-3 at one stage, the Scarlets were forced to endure a spirited fightback from the Premiership side, sparked by replacement Shane Geraghty.

The 20-year-old, a member of England's Six Nations squad, crossed for a try and kicked a couple of penalties to threaten to upset the runaway Pool Five winners.

However, the Scarlets, who struggled to replicate their recent heroics in Europe, managed to hang on with fly-half Stephen Jones landing a late long-range penalty to seal the points and a top seeding for the Welsh region.

The Scarlets were already guaranteed a home draw in the last eight even before kick-off.

Gloucester's win over Leinster at Kingsholm on Friday evening had ensured that, with Leicester's historic victory at Thomond Park the following night setting up Munster as the likely candidates for a trip to Stradey in March.

And showing the same flair and tempo as they have done throughout the pool stages it was the Scarlets who started the brighter against a strong wind.

Fly-half Jones opened the scoring after five minutes with a straightforward penalty shot, before Irish responded through opposite number Barry Everitt after a smart break from Riki Flutey.

But after a series of searing breaks the Scarlets were finally rewarded with their first try on 21 minutes.

The Exiles were shoved unceremoniously off their own scrum ball inside their own 22 and when Alix Popham fed Dwayne Peel, the Wales number nine put his foot to the accelerator and raced through to the line.

Jones converted to make it 10-3 and it soon good worse for the Premiership side.

With his first touch after coming on for the injured Michael Horak, England squad member Geraghty threw out a speculative long pass, only for it to hold up long enough in the wind for wing Dafydd James to pluck it out of the air and race 70 yards unopposed.

The try extended James' lead at the head of the competition's try-scoring chart and with Jones again making no mistake with the simple conversion the Scarlets appeared in total control.

Everitt did manage to reduce the arrears just before the break after Irish won a penalty at a scrum in the home 22, but it was taking some desperate last-ditch defence to keep a confident home side at bay.

However it was the visitors who enjoyed much of the possession and territory after the restart, pounding the Scarlets line with some impressive phase play.

Eventually, with 49 minutes on the clock, it was replacement Geraghty who atoned for his earlier error by darting inside the cover for a well-worked try. The young fly-half added the extras and suddenly Irish were within striking distance.

With Everitt off injured it was Geragthy who was providing the spark for the visitors who were also causing the home side plenty of problems at line-out time.

And they almost took the lead on 65 minutes when number eight Phil Murphy drove over only to lose the ball in the process of touching down.

Irish did manage a penalty however which Geraghty duly landed and with less than a quarter of an hour remaining they were only a point adrift.

But with five minutes left on the clock Jones eased home nerves with a penalty from the halfway line.

Irish could have nicked it in injury time when flying wing Topsy Ojo almost chased down his own kick through, but when replacement lock Nick Kennedy was sin-binned for a reckless punch on Simon Easterby the Scarlets managed to hang on and make it six wins from six in their pool campaign.